


Switch

by majesticartax



Category: Haikyuu!!
Genre: Body Swap AU, Explicit Content to Come, M/M, Masturbation, more tags to come
Language: English
Status: In-Progress
Published: 2019-12-16
Updated: 2019-12-16
Packaged: 2021-03-08 12:42:00
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,916
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21817117
Author URL: https://archiveofourown.org/users/majesticartax/pseuds/majesticartax
Summary: Hinata and Kageyama wake up one morning, transformed.
Relationships: Hinata Shouyou/Kageyama Tobio
Comments: 20
Kudos: 328





	Switch

**Author's Note:**

> WELCOME TO DAY 4 OF THE 30-DAY KAGEHINA CHALLENGE! 
> 
> The first paragraph is a parody of Franz Kafka's "The Metamorphosis" so it may sound a little familiar. 
> 
> <3

One morning, when Kageyama Tobio woke from volleyball dreams, he found himself transformed in his bed into some kind of child. 

He lay on his small back, and if he lifted his head he could see how little space he occupied, the lumps of his limbs beneath the bed sheets stopping short, the fabric covering him so completely it was as if he were drowning within it. His legs, pitifully short compared to the ones he was accustomed to, shimmied and shifted when he peeked under the blankets. 

_ What the actual fuck _ , he thought. It had to be a dream. But his room was all proper and clean and as it should be, lying peacefully between its four walls. A collection of volleyball periodicals lay neatly on his desk, and above it hung a photo that Hinata had recently gifted him from their high school graduation. It was a selfie displaying Hinata’s toothy grin and his arm slung around Kageyama, and Kageyama giving a reluctant peace-sign and a goofy half-smile. The second photo in the series was tucked in his desk drawer, showing Hinata pressing a big kiss to Kageyama’s lips when no one was looking.

He’d smile at the memory, but he’s groggy and irritated that even in a dream he feels tired.

_ Unless this isn’t a dream,  _ something in the back of his mind said. How stupid. 

He threw off the covers and gazed down at himself, blinking the sleep from his eyes; his legs swam in his pajama pants like a couple of logs in a windsock, and his t-shirt bunched around his waist and draped him like a tent. He didn’t  _ feel _ like a child, he just felt smaller. 

He grabbed his phone from the nightstand. 

_ Can you shrink in your sleep?  _ he typed into the search bar before his fingers caught his eye – short and thin with the nails all bitten ragged. Still drowsy, he stared at them, blinking hard. Kageyama didn’t bite his nails. And as his vision cleared and his brain shucked the final dregs of sleep, his pulse began to quicken. 

He wasn’t dreaming. And these weren’t his hands. He shot up in bed and gaped at them. He turned one over and studied the palm, tracing the calloused edges with a finger.

_ No way. _

He fished up his phone again and held it in front of himself, blinking big eyes at his reflection in the dark screen. No. Not  _ his _ reflection.

_ No fucking way. _

He grabbed at the bright hair on top of his head on instinct as his heart rocketed up into his throat.

“Holy shit,” he breathed. “Holy  _ shit!” _

And then the phone rang in his face. Hinata’s contact photo replaced the reflection of Hinata in the screen. Kageyama swallowed and brought the phone to his ear.

“Hinata!?”

**Ten minutes earlier.**

One morning, when Hinata Shouyou woke from volleyball dreams, he––

_ “ _ Wha—huh?  _ WAHH!—Ah?... ahhh…? Ah!? UWAHHH!” _

He found himself—

“ _ YAHHHH!! AHHH!!” _

He—

“ _ FWAAHHH!!” _

Hinata’s long, unwieldy legs snagged in his sheets when he scrambled up out of bed, sending him crashing to the floor as he screamed. 

There was too much of him. Too much and it was  _ everywhere _ . He was everywhere that ever was and ever will be as he flopped about like a fish – arms legs shoulders torso feet hands, the whole excessive mess of him tangled like endless noodles out into the universe to jostle the stars and displace the moon, and when he finally tottered to his giant feet he feared his head would smash through the ceiling, so he dove back into bed and swaddled himself in his giraffe limbs until he was nothing more than a gargantuan lump heaped up and trembling beneath his blankets. 

This was a dream. This  _ had _ to be a dream. So if he just kept his arms and legs inside the bed at all times until the dream came to a complete stop he should reawaken, normal and human-sized once again. He squeezed his eyes shut and then shot them open with purpose, trying to force himself conscious. 

No change.

He did it again.

Still nothing.

Once more.

Nope.

And so Hinata slowly unraveled his limbs and lay flat on his back. He took a deep breath and let it out. Okay. It’s okay. He could figure this out. It  _ had _ always been his dream to grow taller, however having it happen over night just didn’t seem, like,  _ good _ . Or, like,  _ possible. _ It just didn’t make sense. Did he eat something weird? Did he upset a witch? Oh god, was he cursed? It would be a pretty weird curse, though, if that were the case. Being bigger certainly didn’t feel awful, but he didn’t feel like  _ him _ . No. Something else was going on. But what was it? How did this happen? Hinata just needed to think. He needed to concentrate. But on  _ what? _

“Oh god,” he groaned. Even his voice was deeper. How was he supposed to be himself like  _ this? _ But then he gasped. What would Kageyama think!? Would he hate it? Would he break up with him? He wouldn’t, right? Right!? No, that’s ridiculous. Kageyama wasn’t that shallow. Although… Kageyama  _ had _ mentioned several times how much he enjoyed tossing Hinata around while they were, um, intimate. And Hinata loved it too! It was hands down the best thing about their size difference, and Hinata was not ready to give that up. And he loved being able to jump on Kageyama and wrap his legs around his waist while he kissed him, and how comfy Kageyama’s clothes were to wear as pajamas, and how he could burrow into Kageyama’s chest and Kageyama would wrap his arms around him and Hinata felt like he could stay there forever and ever. 

That wasn’t all over now, was it? Hinata didn’t know. He didn’t know anything.

But as Hinata lay there beneath the sheet, staring at the soft morning light filtering through the threads while tears sprung into his eyes, one thing became very clear. 

His sleep shorts were way up his ass.

He sniffled and wiped the back of a dinner-plate-sized hand over his eyes and then tipped his head to look down at himself, tucking a thumb beneath the waistband that was strangling his hips. His eyes roamed down his solid torso to the area where his t-shirt stopped short, exposing most of his abs and the sparse black hairs that trailed down from his navel…

Hinata’s brows pinched. Then they shot up. And then his eyes traced the prominent outline at the front of his shorts. He gulped, and with a shaky hand he lifted the tight waistband to peek at the mass of flesh crammed beneath the thin fabric.

He knew that dick.

Hinata threw off the sheet and launched himself out of bed to galumph across his room, bulldozing the pencil cups and manga off his desk with his steam shovel hands as he grabbed for his small oval mirror. He froze.

Staring back at him were wide blue eyes, and messy black hair stuck out at the sides of his head. And even as this new information crashed over him, Hinata thought, 

_ wow, I’ve never seen Kageyama make that face before.  _

Trembling fingers prodded at Kageyama’s lips and then his cheek. Hinata dropped the mirror when he poked himself in the eye.

His heart pounded with an unfamiliar force and he straightened up as he rubbed his eye with the heel of his hand. His breathing was fast, but the amount of air he drew in felt excessive, took too long to fill his lungs. But a bizarre relief hummed in the pit of his stomach – being Kageyama wasn’t  _ great _ , but somehow it was  _ better _ than just being some nameless giant. He stared at his other hand with a single eye, turning it over in front of his face in shock and wonder. Kageyama’s nails were perfectly manicured. The band-aid that wrapped his middle finger yesterday was gone, but the small cut that it covered was there, half-healed and still tender when he tapped it with his thumb. He blinked both his eyes then and turned his attention to his body again, studying the tight crop-top t-shirt and the shorts that rode up his thighs to scandalous heights. He swallowed hard, then, and peered at the bulge suffocating beneath his clothing. And with a deep breath he peeled the shorts down, wincing at the cut of elastic leaving his hips and scraping down his legs. He tugged the shirt off then, slowly, and then Kageyama stood naked in the center of Hinata’s room. Hinata rolled his eyes down.

Hinata wasn’t proud of it, but if you asked him, now, what it’s like to get turned on by your naked body, he could tell you. 

But, no, this was serious. And even if he  _ was _ Kageyama, and Kageyama  _ was _ his boyfriend, leering at himself felt wrong and disrespectful. Like he was invading Kageyama’s privacy. So he took a deep breath and squeezed his eyes shut to block out the image of his tall, beautiful, exquisitely-toned boyfriend and the pillar that hung between his legs. He lasted about five seconds before peeking open one eye and then the other. His tongue passed over his lips and his fingers twitched at his sides. 

“Stop it you creep,” he hissed, balling his hands into fists. But then again… when would he ever get a chance like this again? One small touch wouldn’t be so bad, would it?

Hinata relaxed his hands and held his breath. He tapped the very tips of the fingers to the outsides of the thighs and slid them up very  _ very _ slowly, jumping when he felt Kageyama’s cock twitch— 

“Shouyou? Are you up?” his mother knocked on the door. “Natsu said she heard yelling.”

“Ye—” Hinata froze and smacked a hand to his mouth, his heart hammering out of control in his chest. Oh shit, shit, he didn’t want to scare his mom with this yet, not until he figured out what was going on. 

“Is everything okay?”

“Y-yeah, just… j-just a minute!” Hinata’s eyes darted around the room and he lunged at the dresser, tearing open the bottom drawer and finding the practice clothes that Kageyama had been leaving at his house.

“Oh… Tobio? Is that you?” Hinata’s mom called. 

Hinata pulled on the clothes in two seconds flat and loped to the door, his feet snagging over the carpet. 

“Yeah, ah, hi!” Hinata said when he cracked the door, peeking out at his mother. He cleared his throat. “I mean hello. Mo––Mrs. Hinata. Good morning.”

Hinata’s mother blinked up at him. “Oh, good morning Tobio,” she cocked her head. “Are you sick? Your voice is… strange.”

Hinata inwardly kicked himself for intentionally deepening his voice. He wasn’t  _ pretending _ to be Kageyama, he  _ was _ Kageyama.

“N-no, I’m fine,” Hinata cleared his throat again, speaking in Kageyama’s normal tone and angling his shoulders strategically when his mom tried to look into the bedroom. 

“I didn’t even know you slept over!” she said, smiling warmly. “Is Shouyou awake? Natsu wanted pancakes so I need to know how many to make. Would you like some?”

“U-um, no, he’s not awake yet,” Hinata whispered and took a quick glance back into his bedroom for effect. He looked down at his mom then, taking in this brand new point of view. And to his surprise he didn’t… love it. He felt so far away and kind of exposed, way up there. Maybe being tall was something you needed to ease into.

Mrs. Hinata’s expression turned confused. “So you two weren’t yelling in here?”

“Oh, uh, no, I mean yes, we were, I—he was. No I was. I yelled.” Hinata felt like a deer in headlights. “Sorry for yelling. Um. M-ma’am.” 

“You yelled… by yourself?”

“T-there was a spider.” Hinata gave an embarrassed laugh that sounded utterly insane and alien in Kageyama’s voice and rubbed at the back of his neck. He tried to smile but the muscles felt all wrong and he was pretty sure he was just baring his teeth at his mother. He relaxed his mouth.

“Oh… I see,” his mom said slowly. “And Shouyou didn’t wake up from that?”

Hinata shrugged. But his mother continued to stare up at him with a look of concerned interest. She stuck her hands to her hips.

“Is there something wrong, Tobio?”

Hinata’s eyes widened and he shook his head.

“You could tell me if there was, you know,” his mom told him, narrowing her eyes and rising up onto her toes to stick her face up closer to his. “Maybe I could help.”

Hinata resisted the urge to back away. “Everything’s fine, really!” he said.

His mom stared at him for a few more tense seconds but then she smiled big and her heels touched back down onto the floor. 

“Okay then! Wake Shouyou up soon. I’m taking Nastu out shopping but I’ll save some pancake batter for you. Ugh, you’re so handsome” She reached up and ruffled Hinata’s hair before turning and walking away. “And don’t make a mess,” she added over her shoulder.

Hinata let his head flop forward in relief before closing his door. He immediately dashed back to his bed, stumbling all over his gigantic fucking feet and falling to his knees before manhandling the shit out of his phone with tremulous hands. He jabbed at Kageyama’s number. The line rung.

_ “Hinata!?” _

Hinata sucked in a breath at the sound of the high voice before choking out, “Kageyama!?”

_ “Am I—are you—is this—” _

“I-is it you, too?” Hinata rasped as tears began to pour from his eyes. “Kageyama? A-are you… are we…?”

_ “H-hold on. This… this isn’t something that can happen, right?” _

“Obviously it did!” Hinata yell-whispered, sniffing hard.

_ “I could be a dream!” _

“People don’t share dreams!”

_ “People don’t switch bodies either, idiot!” _

“Don’t yell at me, I’m  _ stressed! _ ” Hinata cried, immediately throwing a hand over his mouth to muffle his voice. “What are we supposed to do!?”

_ “I’m stressed too!”  _ Kageyama hissed, but then his voice turned soft.  _ “And jesus please stop crying.” _

“But I c-can’t!” Hinata sobbed, falling onto his butt on the floor and leaning back against his bed with a hand over his face. “I-I’m just s-so… so relieved that it happened to you too.”

_ “What!?” _

“I-I’m so happy—” he hiccuped “—that I’m not alone!”

Kageyama exhaled a long, slow breath.  _ “You wouldn’t be alone either way, dumbass _ .”

“Really?” Hinata sniffled, wiping his nose with the hem of Kageyama’s shirt.

_ “Of course not. I’d help you.” _

“Yeah, but… would you want to date yourself?”

_ “Um… not exactly but—” _

“S-so you’d leave me?” Hinata’s voice shrank to a squeak and he pulled his knees to his chest.

_ “No! God, will you listen? You wouldn’t be  _ me _ , you’d still be you, you’d just look different.” _

“Yeah, and everyone would think you were in a relationship with your twin,” Hinata mumbled.

_ “How the hell would anyone know we were in a relationship? It’s not like we’d fuck in the street.” _

Hinata snuffled out a laugh. As alien and unpleasant as his own voice sounded over the phone, hearing Kageyama’s words in its higher register was pretty funny.

_ “Are you done crying now? Hearing myself like that is creeping me out.” _

“Oh, like you’ve never cried.”

_ “I definitely don’t blubber and whine like a big baby.” _

Hinata scoffed. “Yeah well, we have the rest of our lives to change that.”

_ “Is that a threat?” _

“No. Can you come over?” Hinata shakily climbed to his feet. He couldn’t help duck his head, it was super weird being so close to the ceiling.

_ “Yeah, just give me a few… oh wait. Shit. How am I supposed to get out?” _

“Are your parents home?”

_ “I don’t know! I can’t exactly go look!” _

Hinata frowned. “Why not? My mom already saw me. Er, I mean,  _ you. _ She assumed you slept over and I was still asleep. She and Natsu are leaving for the day so it would be safe here.”

Kageyama groaned.  _ “You can’t just come here?” _

“No.”

_ “Why not?” _

“Because… there’s pancakes here.” Hinata mumbled. “And being you is making me super hungry!”

Kageyama sighed in exasperation, but then he laughed quietly. Hinata’s voice turned it into a giggle. 

_ “Fine, I’ll figure out a way to get there.” _

“‘Kay.” Hinata sighed. “Um… I’m sorry this is happening.”

_ “Why? Did you make it happen?” _

“I don’t think I’d know how to do that.”

_ “So shut up then.” _

“Yeah but… it’s probably worse for you. You  _ shrunk.” _

_ “I haven’t noticed much of a difference. I haven’t even stood up yet.” _

“Oh. Well… enjoy, I guess.”

_ “How does it feel to be tall?” _

“Actually it’s not that great. There’s too much of me. It's not supposed to happen all at once! ”

_ “Hm. Yeah. I wonder what it will be like to play like this.” _

Hinata’s eyes felt on the verge of filling with tears again. “I-I don’t want to think about that! I can barely even walk!” he whimpered. “Just get over here?”

_ “I’m coming! I still have to get ready. God, how am I supposed to get in the shower?” _

Hinata rubbed his eyes and shrugged. “Sneakily?”

_ “I guess.  _ _ Although… showering as you is going to be interesting...” _

Hinata’s face went hot and he stomped his foot. “Don’t you dare molest me!”

_ “I’m kidding, stupid.” _

“No you’re not! You keep your hands to yourself!” Hinata yell-whispered. “Or my hands… whoever’s hands!”

_ “Why? It’s not like you'll know. And since when don't you want me touching you?” _

Hinata scoffed. Kageyama was right - Hinata was never _not_ thirsty for Kageyama. “Fine then. I’ll just be over here putting things in your butt.”

_ “If you must.” _

Hinata wrapped a long arm around himself and sighed. “Just please hurry.”

Kageyama sighed back.  _ “I love you. We’ll figure this out.” _

“I love you too,” Hinata whispered. He sagged where he stood, suddenly exhausted and very very afraid. But he knew Kageyama was right. He wasn’t alone, and they’d figure it out. The question, though, was _how soon?_ College started in a few weeks… _volleyball_ started in a few weeks.

_ “I’ll be there in an hour. Maybe less.” _

“mkay, bye Kageyama.”

Hinata hung up the phone and dove back into bed.

..

Hinata had cried for only a few minutes more before dragging his own giant ass to the bathroom to shower, first checking that the coast was clear and his house was empty. It was. 

The first half of the shower was spent staring at himself in the large mirror in the bathroom, the water left running and half-forgotten as he lovingly admired every inch of skin that wrapped the man he adored; knowing that Kageyama possessed his body too made him feel less guilty about staring. But Hinata was surprised to find that there was very little about Kageyama’s body that he didn’t already know, visually, anyway. Well, not  _ surprised,  _ really. They’ve enjoyed literally thousands of hours with each other in the six months they’ve been dating, naked and otherwise, not to mention all the time they spent together before, and it wasn’t unusual for Hinata to lie in bed with Kageyama and study him – his muscles and joints and bony places, hidden beauty marks and scars, the birthmark on his butt that Kageyama didn’t even know he had. Hinata had seen it all, and yet the little study sessions never lost their significance. 

Things didn’t feel quite so special now, however, without Kageyama  _ inside _ his body. But it was still worth exploring. And Hinata was  _ fascinated _ by how simple touches and movements that he was accustomed to in his own body felt so different in Kageyama’s. You really don’t appreciate how well you know own body until it’s gone. Or, rather, misplaced. Things he’d done daily for years and years were suddenly so foreign he had to concentrate hard to do them, lest something go awry.

For example, peeing.

For another example, brushing his teeth. He had to hold the brush, bring it to his mouth, _find_ his mouth with the head, find where to press the bristles to not scrub at his gums, figure out how far back to stick the brush to get all his teeth but not so far back that he sticks the thing in his throat and when to change the angle of the brush and how to keep the toothpaste from dribbling all down his chin and  _ holy shit _ Kageyama’s gag reflex was an absolute nightmare. How the hell did he suck Hinata’s dick?

He decided not to think about that too hard.

And the way things  _ felt _ were so unexpected. He never thought about the feeling of washing his hair before, but all the skin on his torso erupted into goosebumps the moment he scrubbed shampoo over his scalp. It felt  _ amazing _ . So of course Hinata had to figure out what other places on Kageyama’s body were more sensitive than his own. Kageyama’s stomach was one – even under his own touch, a light caress right above his navel made him shiver beneath the warm water. The backs of Kageyama’s arms were another and so were his hip bones.

Hinata would have to use this information in the future. He’d get to. He  _ would _ .

But on the other hand, Hinata realized that the most sensitive places on his own body did not translate to Kageyama’s. While the right kind of touch to Hinata’s nipples could make him moan and tremble (he could do it to himself, too), Kageyama’s nipples barely had any feeling at all. And Hinata really cranked on those things; all he succeeded in doing was giving Kageyama a bruise.

“Sorry ‘yama,” he muttered, rubbing at his chest. 

His ass and thighs were similar. 

Hinata swallowed when his gaze fell again to his cock. He’d already touched it to pee, so…

A noise huffed out of him when he wrapped a big hand around himself. All the touching and prodding and experimenting had him half-hard, and it only took a couple of full strokes to get him the rest of the way. Okay, yes. Good. He and Kageyama were on an even keel when it came to this part – sensitivity-wise, anyway.  He leaned a hand to the tile and dropped his head beneath the water as he stroked himself. It wasn’t particularly remarkable – in fact, it almost didn’t feel any different than when he did it to himself, like, in his own body. Which was… strange, he thought. And oddly disappointing. But it still felt good and he came beneath the heat of the water with a quiet gasp and a jerk of his hips. But he'd have enjoyed it so much more if things didn't feel so scary.

They'd figure it out.

He finished his shower, cleaning Kageyama’s special areas extra thoroughly, just as a courtesy, and toweled off before pulling on Kageyama’s practice clothes again and trotting back to his bed. His phone showed a text from Kageyama from eight minutes ago:

_ on my way.  _

And a text from one minute ago: 

_ had to lower my bike seat. now on my way _

Hinata gave a short laugh and flopped onto his back. He laid there staring at the ceiling for several minutes, thinking and mulling and ruminating, but then he frowned. Hinata could barely walk.

How the hell could Kageyama ride a bike?

**Author's Note:**

> I might rewrite a lot of this. I'm not thrilled with the pacing or the tone but eh. Can't win them all! I probably should have planned to make this a much longer fic. We'll see how it goes. I'm VERY EXCITED to post the second part. It's something I've been wanting to write for three years :D
> 
> Thanks for reading!
> 
> tum & twit @majesticartax


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